Hello all, new member here. I have a "new to me" 2000 4.0 auto 4wd cherokee. It runs @210 when driving, mabe 220 when idling. If I shut it off and restart within 5-10 mins, Temp guage is pegged at 260, check guages light on. after about 1 min temp starts to drop, and goes back to 210. I have changed t-stat, coolant looks good, e-fan works and clutch fan runs about 1000 rpm at idle. any thoughts??

I did search forum, but couldn't find a thread about this specific problem

Glen

 

Sounds like an airflow issue.
Check the clutch fan, and make sure your radiator and a/c condensor is not plugged with bugs dirt, etc.

 

Thanks for the reply. If spin the fan by hand, there is some resistance. Is there a better way to check a fan clutch?

 

it could be air flow but i would also check for an air pocket. when off the air goes to the t/stat housing (where the ECT sits) and if coolant is not on the sensor, the sensor will read max hot, until you bump the throttle to get things moving around and the air goes past it causing it to drop back to 210. (but this would make it drop back to 210 pretty fast. and it can cause the coolant to not circulate at idle because the air blocks it. have you propperly "burbed" the coolant? or just filled it and ran it?

 

when it is cranked, it does drop quickly... What is the best way to "burp" the system?

 

take the cap off when cold and run it till its about to overflow then shut it off... least thats what worked for me!

 

Thanks! I do that

 

Pull the temp sensor at the back of the head, pull it out and you can "burp" the system. You can do it cold too.

 

'00 models don't have a sensor in the back of the head.....just one in the t-stat housing. They are self burping, the rad cap is the highest point in the cooling system.

 

I would look at changing the temp sensor. It sounds like its off. Not to discount what others are telling you, but this could be a simple solution.

 

The best way is to replace the old fan clutch with a new one. They start loosing efficiency from day one and yours could be 11 years old.